Fish is new weapon in fight against dengue in Philippines

Manila: Experts are rediscovering an ancient weapon in the fight against dengue — one that is so commonplace that its significance in controlling the mosquito population has been all but lost to most Filipinos.

The kataba or tuyong — top minnow or mosquito fish in English (scientific name: Gambusia affinis) — is regarded as useless river and pond dweller to most in the Philippines, but there was a time that these fish were used by the government to control mosquito populations.

“Mosquito fish was introduced all over the world to control malaria and perhaps health officials have forgotten about its existence in the Philippines,” Dr Westly Rosario, head of the Bureau of Fisheries and Aquatic Resources (BFAR) National Integrated Fisheries Technology and Development Centre was quoted in reports as saying.

The American colonial government introduced the mosquito fish in the Philippines during the early 1900s as part of efforts to control the spread of malaria.

With an appearance similar to anchovy, but smaller, the mosquito fish got its Tagalog name, kataba, because of its bulging belly. It’s known as the mosquito fish however, because of its ability to eat large amounts of mosquito larva.

Mosquito larva thrive in stagnant or unmoving water while the mosquito fish is hardy and can survive even in highly polluted water. This makes it highly suitable for eliminating not only ordinary mosquito larvae but dengue virus carrying Aegis Egyptii mosquito larvae as well.

The BFAR is studying the possibility of promoting the propagation of the mosquito fish in more areas of the country that are at high risk of having dengue outbreaks.

Recently, several hundred mosquito fish were released in sewer passages in Pangasinan in Central Philippines as part of pilot efforts.

Currently the Philippines has a number of countermeasures against dengue including the use of mosquito ovicidal/larvicidal (OL) traps.

The mosquito OL traps were introduced in 2011 across the country. They are simple and cost-effective devices that consist of a black tumbler, a wooden board and pellets that encourage dengue-carrying mosquitos to lay their eggs in the trap.

Dengue is a disease that claims the lives of hundreds of Filipinos every year.

In Metro Manila alone, the number of people afflicted has surpassed the 4,000 level from January to July according to the Department of Health. Of this number of victims, 10 were listed as fatalities.

All over, the country, 193 deaths have been recorded from a total of 42,207 dengue cases. The health departments’ National Epidemiology Centre said the country is continuing to experience a declining number of dengue deaths as a result of government interventions.